enigo

So this morning after much rejoicing of getting the leaking axle seal replaced with no hiccups on my car, I begin my 5 hour drive to Chicago running a little bit late. Figuring it'll be close, but I can make in on time. Well... that didn't happen.

About 30 minutes into the drive, the engine cuts out suddenly. I'm going about 70 mph on the interstate. So I pull over, befuddled as to what the problem is. I can't start the engine. It turns over, makes the whirring noise, but no pops, no ignition. I look all over the engine bay for any sign of leaks, breakage, anything. I find nothing.

I figure its someone to do with the fuel pump, since it seemed like everything was working, but no gas was getting to the engine.

This whole time, I forget to check the fuses.

So, I call a tow truck and they haul me to their shop. That in itself was a frustrating experience. I tell em, I just replaced the engine, and I know the car fairly well, so if you have any questions please ask me. I'm told I can't go on the shop floor for insurance reasons. The guy working on the car takes an 20 minutes checking the spark plugs, checking the wires... then he spends another 20 minutes on the computer... to look up how to get to the fuel pump. Whole time I'm standing at the counter watching trying to figure out what he's doing. He's some quiet guy that studiously avoids looking at where I'm at. So after an hour, I call a friend I was supposed to meet in NYC, and let him know whats going on, when it dawns on me that I haven't checked the fuses, and I say as much.

End of the phone call, I hear the car start up, and I see the fuse box lid off... The 20 amp ECU fuse had blown, and was causing nothing to reach the engine. So... I ended up paying $110 for a fuse...

At this point I've missed my flight, so I just drive home. About 6 miles out, the exact same problem crops up... I had the AC n Radio on at the time. So I call up the shop, and they agree to send me a fuse in a truck. So the guy comes and is generous and gives me 2 fuses. I leave the radio off, I turn off the AC, and I drive... for about 5 minutes, and then the fuse blows. I think maybe the radio install I did might have caused this short, so I disconnect the radio from the plug. I put the 2nd fuse in, and go... maybe 3 minutes this time, the fuse blows.

I decided to completely cut out the radio harness I had just installed in an act of desperation. A guy pulls up and suggests that I use some thin wire to bridge the fuse, so it won't blow so I can get to town at least. So I do that... and get to drive about 7 minutes till the engine dies again. I inspect the wire, and it looks like its still engaged, but a bit blackened. Car won't start. I wonder if I damaged something, so I put the AC 20 amp in the ECU slot, and it kills that fuse right away when I try to start the car.

Sooo... WTF?

Would a radio install cause the ECU fuse to go? (wires carefully lined up with the right ones)

What causes an ECU fuse to go?

What can I do to fix the problem?

I can install a 1.8 ECU...

I can replace camshaft sensor

Known issues:

The TPS is throwing a code (its a Kefico that was working fine in the previous car)

Camshaft Position sensor throwing a code, but because I hadn't had it plugged in all the way.

Bolt on alternator broke during removal. Instead of wire smashed between 2 nuts, I substituted a washer for one, and used one nut.

For the Battery Terminal install, i had to take of a small chunk of wire to get it in terminal clamp on both ends.


How can I fix this problem??

Gosh... its been one problem the next for me

blacktibby

Dang i wrote a long response then my computer crashed.

Well i think it's a poor / Broken ground in your wiring harness. I would check your wiring harness connections along with the alternator connections.

Also don't bridge connectors. If the melting point of the wire is higher then that of your harness you mess up your harness.

Just my 0.02Cents

REDZMAN

Hmm, you swapped to a Beta 2 right?

Did you use the Beta 2 alternator?

enigo

No, I'm using the Beta 1 alternator.

I just re-did the main ground off the wiring harness next to the battery, so I believe that one is okay.

This seems like a pretty serious short that has cropped up... Since its just one fuse that is blowing, what are all the things linked to it that could be causing that fuse to blow?

I can check on the alternator wiring when I go back out there... but I taped it pretty well in place to be secure.

This hasn't happened in all the city driving I was doing before I got out on highway... what would cause this problem to only show up in highway driving?

EDIT:

Okay... if it was the alternator or an issue with that, I'd expect more than just this fuse blowing over and over right? My cutting out my radio install was a stupid kneejerk reaction... but I blame it on having no sleep the night before and frustrated. Also fueled by the shop's mechanics remark that aftermarket radios are known to do this stuff...

Here is what I've come up with. I'm blowing Fuse B.



This is the Harness that is being problematic. It has 2 ground points: G10,11 These grounds are under the dash.. hard to get to, and I doubt came loose.


Below is the schematic for the fuse thats repeatedly blowing, and whats its connected to. I doubt the TPS has anything to do with this based on these schematics, its wiring is pretty much free of fuse that is repeatedly blowing. The CMP does connect to the engine control relay, which then goes to the said fuse. So it might have something to do with this. This is based on the assumption that the error code I as getting with it eventually led to the sensor shorting out.




Though what this could mean is that somewhere along the fuel pump line, I have bared wire... I don't know for sure.

My only test that I have available to me is to take the CMP from the other car and stick it on this one and see what happens... The shop mechanic that took an hour to realize it was the fuse had been testing the wires on the fuel pump, and when I asked him whether or not everything else was alright, he mumbled 'should be.' I don't have the equipment he did, so I'm hoping that its the error-code throwing CMP...

Going to try and take a look at it tonight once I find someone to drive me out to the car... with a flash light, and 2 20 amp fuses from the old car.

radu_rd2

First of all, why didn't you took out other fuses and used those before calling the truck? There are a ton of non-critical fuses (turn lights, radio, etc).

You shouldn't have put that wire in there.. now since it stopped working anyway, and the wire was still making the connection, something else must have blown up.. sorry. Maybe you're lucky and it's another fuse, so check all of them right away. If you find that another fuse blew, check the schematics to find out what wirings do the two fuses have in common.

It's most likely a short somewhere.. your schematics show that that wire goes to the oxygen sensors, so check those first. Maybe you nicked a wire when you were struggling with that axle..

First thing I would do: unplug the rear oxygen sensor, and using a multimeter check the resistance between that wire (pin 4) and a ground. If the resistance is not huge, there must be a short on that wire (could be anywhere tho). Also check for the same thing on the sensor side, maybe it's the oxygen sensor (check between that pin and the oxygen sensor metal body). Second thing to do would be a similar check at the connector near the fuel pump.

Good luck.

enigo

I didn't think to check the fuses the first time the engine died. The way it died made me think loss of spark, fuel pump failure. Fuse just didn't come to mind... maybe if I had gotten some sleep last night I would have been more clear. I already used every single 20 amp fuse I had available. I now have 2 more from the other car.

The shop mechanic checked the fuel pump wires, and didn't make any comment about those. So I'm assuming those will be alright. This harness seems pretty self-contained, and doesn't have items going to multiple fuses. I already checked to see if others were blown.

I'll try and get the car jacked up and check whats going on with the sensors. There is a train I'm going to have to catch by tomorrow early, as well as some more stuff that needs to be done, since I'm still around, for work. (Yeah, I'm not getting any slack here). So I have very little time for car work.

The thingsI have to look at, the MAF, O2 Sensors, CMP, and the Engine Control Relay. Hopefully something will come out lookin' wrong that can be disconnected/replaced.

blacktibby

Under dash grounds? huh? what? No .. Check all the wiring that would have been affected by the engine swap, as in the one connected to the engine. If you find nothing out of place. Check all sensor lined that coulds have got stretched / Broken.

supercow

^^pretty much the only option is to go over everything you worked on with a fine tooth comb till you find it.

with a motor swap its super easy to hack off a wire and not notice till it causes issues.

btw, the battery has one ground going to the motor and one to the frame. Make sure both are hooked up. Might wanna clean them up with come electrical cleaner.

zoned019

I had a similar experience a few months ago. Got my car towed home (ilegally with my dad's SUV and a tow rope though), spent a bunch of time on the side of the highway, almost missed my first day of work at my new job .. horrible experience, all because of the damn ECU fuse. If I would have been smart enough to check it, I could have saved so much hassle if someone would just bring me a 20A fuse, some crimp connectors, and electrical tape.

Mine also kept blowing after I would replace it.

I ended up fixing mine by fixing a short in the o2 sensor wires (replaced them). Not sure if that's your problem, but that's what mine was. I had a pretty good idea because I had just replaced my headers so it was much easier to narrow down than your issue.

enigo

Well here is the ground that I was talking about that is for this circuit:



Just a quick update... one that makes me never want to use a NAPA shop again. What caused the problem, was the Rear O2 sensor connector. It had fallen down and rested on the exhaust pipe, melting when the pipe got hot. Causing the short...

Extremely easy to spot once you get the car up. How the shop guy didn't notice it is beyond me.

The connectors are both completely fried... so I'll need new harness and sensor side connections. (Probably steal them from other car again)